1. Technical Field of the Invention
The invention relates generally to wireless communication systems; and, more particularly, it relates to adaptive channel allocation for video stream transmissions.
2. Description of Related Art
Many approaches for improving video error robustness/concealment have been proposed, and these approaches can generally be divided into two groups. The first group is related to network layer solutions that attempt to recover the error/packet loss at packet layer, by providing an error free A/V stream to the video decoder. Such solutions usually require redundant codes and retransmissions. The second group is related to video layer solutions, especially post-processing, that will accept a corrupted video stream and try to mitigate gaps and mismatches in the decoded video frames.
As may be understood, both of these groups (network layer solutions and video layer solutions) have their strengths and weaknesses. In particular, a heavily protected network layer might be very robust and resilient to errors, but usually this is accompanied by a reduction in the constant throughput of the channel and/or an increase in the effective latency of the channel. For the video layer, one of the primary considerations is the overall user experience (e.g., the perceptual experience of a user). Video should appear smooth and natural, even under variable network conditions. Under variable channel conditions, providing an acceptable user experience can be particularly challenging for real-time (or near real-time) video streams, as both packet loss and channel delay can have deleterious effects on perceived video quality (e.g., blocking or blurring effects, video freezing or jerkiness, and audio/video synchronization issues).
More particularly, during real-time video encoding and transmission, a packet transmission incremental delay that causes the packet to arrive at the receiver after the time it is needed for decoding might have the same effect as an expired or lost packet. The video decoder typically needs to decode and present each video frame within a relatively short time period. Consequently, if a packet is delayed too much over the network it might be impossible to complete frame decoding in time for display. If a delayed or dropped frame is also a reference frame for other frames, decoding errors for multiple frames may occur. Particularly in the context of wireless communications under noisy channel conditions, the present art does not provide an adequate means by which communication of video/media related content may be effectuated in a robust, reliable, and perceptually acceptable manner.